The plant fossil record reflects just two great extinction events

When one hears the term “ground cover,” one immediately thinks of “grasses.” This perception is so deep-seated that paleobotanists even have been overheard to proclaim that “there was no ground cover before grasses.” Today grasses are so predominant in many environments that this perception is perpetuated easily. On the other hand, it is difficult to imagine the absence or lack of ground cover prior to the mid-Tertiary. We tested the hypothesis that different forms of ground cover existed in the past against examples from the Recent and the fossil record (Table 1). The Recent data were obtained from a large number of sources including those in the ecological, horticultural, and microbiological literature. Other data were derived from our knowledge of Precambrian life, sedimentology and paleosols, and the plant fossil record, especially in situ floras and fossil “monocultures.” Some of the data are original observations, but many others are from the literature. A detailed account of these results will be presented elsewhere (Pfefferkorn and LePage, in preparation).

Download Full-text

Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period

Biogeosciences Discussions ◽

10.5194/bgd-7-3969-2010 ◽

2010 ◽

Vol 7 (3) ◽

pp. 3969-3999 ◽

Cited By ~ 3

Author(s):

C. Albrecht ◽

H. Vogel ◽

T. Hauffe ◽

T. Wilke

Keyword(s):

Sediment Core ◽

Fossil Record ◽

Interglacial Period ◽

Ancient Lake ◽

Last Interglacial ◽

Lake Ohrid ◽

Last Interglacial Period ◽

History Of ◽

Extinction Events ◽

Mollusc Shells

Abstract. Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR) dating of mollusc shells from the same stratigraphic level yielded an age of 130±28 ka. Lithofacies III sediments, i.e. a subdivision of the stratigraphic unit comprising the basal succession of core Co1200 between 181.5–263 cm appeared solid, grayish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70%) and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species) could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated. The agreement between sediment and palaeontological proxies was tested. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial period. We tested for major faunal changes since the Last Interglacial period and searched for signs of extinction events. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m) mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also has great significance for future deep drilling projects. It can be hoped that a more far reaching mollusc fossil record will then be obtained, enabling insight into the early evolutionary history of Lake Ohrid.

Download Full-text

3. Extinction in the past

Extinction: A Very Short Introduction ◽

10.1093/actrade/9780198807285.003.0003 ◽

2019 ◽

pp. 33-50

Author(s):

Paul B. Wignall

Keyword(s):

Fossil Record ◽

The Past ◽

Extinction Rates ◽

History Of ◽

Extinction Events

Despite the less-than-perfect nature of the fossil record, it still provides a unique window on the history of life, and reveals that there have been dramatic fluctuations in extinction intensities since complex life evolved around 600 million years ago. ‘Extinction in the past’ considers Jack Sepkoski’s database compiled in the 1980s, and his series of highly informative charts showing both diversity and extinction rates since the start of the Cambrian Period 541 million years ago. The calculation of extinction rates and the improved dating of extinction events are discussed, along with the extinction trends that can be observed. Fossils also provide valuable evidence on the nature of selection during extinction.

Download Full-text

How predictable is extinction? Forecasting species survival at million-year timescales

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2019.0392 ◽

2019 ◽

Vol 374 (1788) ◽

pp. 20190392 ◽

Cited By ~ 2

Author(s):

Peter Smits ◽

Seth Finnegan

Keyword(s):

Fossil Record ◽

Human Impacts ◽

Rank Order ◽

Extinction Risk ◽

Geographical Range ◽

The Past ◽

The Future ◽

Out Of Sample ◽

Extinction Events ◽

Over Time

A tenet of conservation palaeobiology is that knowledge of past extinction patterns can help us to better predict future extinctions. Although the future is unobservable, we can test the strength of this proposition by asking how well models conditioned on past observations would have predicted subsequent extinction events at different points in the geological past. To answer this question, we analyse the well-sampled fossil record of Cenozoic planktonic microfossil taxa (Foramanifera, Radiolaria, diatoms and calcareous nanoplankton). We examine how extinction probability varies over time as a function of species age, time of observation, current geographical range, change in geographical range, climate state and change in climate state. Our models have a 70–80% probability of correctly forecasting the rank order of extinction risk for a random out-of-sample species pair, implying that determinants of extinction risk have varied only modestly through time. We find that models which include either historical covariates or account for variation in covariate effects over time yield equivalent forecasts, but a model including both is overfit and yields biased forecasts. An important caveat is that human impacts may substantially disrupt range-risk dynamics so that the future will be less predictable than it has been in the past. This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?’

Download Full-text

Fossil-calibrated molecular phylogeny of atlantid heteropods (Gastropoda, Pterotracheoidea)

BMC Evolutionary Biology ◽

10.1186/s12862-020-01682-9 ◽

2020 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Deborah Wall-Palmer ◽

Arie W. Janssen ◽

Erica Goetze ◽

Le Qin Choo ◽

Lisette Mekkes ◽

...

Keyword(s):

Fossil Record ◽

Large Scale ◽

Global Scale ◽

The Other ◽

The Past ◽

The Family ◽

Rapid Diversification ◽

Maximum Likelihood Phylogeny ◽

Extinction Events ◽

Ribosomal Rrna

Abstract Background The aragonite shelled, planktonic gastropod family Atlantidae (shelled heteropods) is likely to be one of the first groups to be impacted by imminent ocean changes, including ocean warming and ocean acidification. With a fossil record spanning at least 100 Ma, atlantids have experienced and survived global-scale ocean changes and extinction events in the past. However, the diversification patterns and tempo of evolution in this family are largely unknown. Results Based on a concatenated maximum likelihood phylogeny of three genes (cytochrome c oxidase subunit 1 mitochondrial DNA, 28S and 18S ribosomal rRNA) we show that the three extant genera of the family Atlantidae, Atlanta, Protatlanta and Oxygyrus, form monophyletic groups. The genus Atlanta is split into two groups, one exhibiting smaller, well ornamented shells, and the other having larger, less ornamented shells. The fossil record, in combination with a fossil-calibrated phylogeny, suggests that large scale atlantid extinction was accompanied by considerable and rapid diversification over the last 25 Ma, potentially driven by vicariance events. Conclusions Now confronted with a rapidly changing modern ocean, the ability of atlantids to survive past global change crises gives some optimism that they may be able to persist through the Anthropocene.

Download Full-text

Modeled physiological mechanisms for observed changes in the late Paleozoic plant fossil record

Palaeogeography Palaeoclimatology Palaeoecology ◽

10.1016/j.palaeo.2020.110056 ◽

2021 ◽

Vol 562 ◽

pp. 110056

Author(s):

Jon D. Richey ◽

Isabel P. Montañez ◽

Joseph D. White ◽

William A. DiMichele ◽

William J. Matthaeus ◽

...

Keyword(s):

Fossil Record ◽

Late Paleozoic ◽

Physiological Mechanisms ◽

Plant Fossil

Download Full-text

Estimating the number of pulses in a mass extinction

Paleobiology ◽

10.1017/pab.2016.30 ◽

2018 ◽

Vol 44 (2) ◽

pp. 199-218 ◽

Cited By ~ 1

Author(s):

Steve C. Wang ◽

Ling Zhong

Keyword(s):

Mass Extinction ◽

Fossil Record ◽

Nearest Neighbor ◽

Hypothesis Test ◽

Information Criterion ◽

Data Set ◽

Recovery Potential ◽

Step Algorithm ◽

Extinction Events ◽

Fossil Preservation

AbstractThe Signor-Lipps effect states that even a sudden mass extinction will invariably appear gradual in the fossil record, due to incomplete fossil preservation. Most previous work on the Signor–Lipps effect has focused on testing whether taxa in a mass extinction went extinct simultaneously or gradually. However, many authors have proposed scenarios in which taxa went extinct in distinct pulses. Little methodology has been developed for quantifying characteristics of such pulsed extinction events. Here we introduce a method for estimating the number of pulses in a mass extinction, based on the positions of fossil occurrences in a stratigraphic section. Rather than using a hypothesis test and assuming simultaneous extinction as the default, we reframe the question by asking what number of pulses best explains the observed fossil record.Using a two-step algorithm, we are able to estimate not just the number of extinction pulses but also a confidence level or posterior probability for each possible number of pulses. In the first step, we find the maximum likelihood estimate for each possible number of pulses. In the second step, we calculate the Akaike information criterion and Bayesian information criterion weights for each possible number of pulses, and then apply ak-nearest neighbor classifier to these weights. This method gives us a vector of confidence levels for the number of extinction pulses—for instance, we might be 80% confident that there was a single extinction pulse, 15% confident that there were two pulses, and 5% confident that there were three pulses. Equivalently, we can state that we are 95% confident that the number of extinction pulses is one or two. Using simulation studies, we show that the method performs well in a variety of situations, although it has difficulty in the case of decreasing fossil recovery potential, and it is most effective for small numbers of pulses unless the sample size is large. We demonstrate the method using a data set of Late Cretaceous ammonites.

Download Full-text

Neogene precipitation, vegetation, and elevation history of the Central Andean Plateau

Science Advances ◽

10.1126/sciadv.aaz4724 ◽

2020 ◽

Vol 6 (35) ◽

pp. eaaz4724 ◽

Cited By ~ 1

Author(s):

C. Martínez ◽

C. Jaramillo ◽

A. Correa-Metrío ◽

W. Crepet ◽

J. E. Moreno ◽

...

Keyword(s):

Fossil Record ◽

Climate Model ◽

Regional Climate ◽

High Elevation ◽

The Andes ◽

Plant Fossil ◽

History Of ◽

Andean Uplift ◽

Climate Model Simulations ◽

Fossil Data

Andean uplift played a fundamental role in shaping South American climate and species distribution, but the relationship between the rise of the Andes, plant composition, and local climatic evolution is poorly known. We investigated the fossil record (pollen, leaves, and wood) from the Neogene of the Central Andean Plateau and documented the earliest evidence of a puna-like ecosystem in the Pliocene and a montane ecosystem without modern analogs in the Miocene. In contrast to regional climate model simulations, our climate inferences based on fossil data suggest wetter than modern precipitation conditions during the Pliocene, when the area was near modern elevations, and even wetter conditions during the Miocene, when the cordillera was around ~1700 meters above sea level. Our empirical data highlight the importance of the plant fossil record in studying past, present, and future climates and underscore the dynamic nature of high elevation ecosystems.

Download Full-text

Major Patterns in Botanical Diversity

The Paleontological Society Special Publications ◽

10.1017/s2475262200014076 ◽

1999 ◽

Vol 9 ◽

pp. 171-186

Author(s):

Peter R. Crane

Keyword(s):

Fossil Record ◽

Pollen Grains ◽

Terrestrial Ecosystems ◽

Plant Evolution ◽

Cambrian Explosion ◽

Fossil Plants ◽

Plant Parts ◽

Plant Fossil ◽

Public Consciousness ◽

The Rich

At a time when the popular perception of paleontology is dominated by images of dinosaurs and other spectacular vertebrates, or the mysteries surrounding the Cambrian “explosion” of animal life, it is perhaps not surprising that the rich and informative fossil record of plants has scarcely made an impact on the public consciousness. In reality, as one would expect from those organisms that comprise the bulk of the biological material in terrestrial ecosystems, the fossil record of plants is extensive (Stewart and Rothwell, 1993). Leaves, wood fragments, pollen grains, spores, fruits, seeds and other plant parts are the most common fossils in rocks deposited in ancient flood plains, lakes and many other environments - and they are often exquisitely preserved. This excellent fossil record provides important information about the ecology of ancient terrestrial ecosystems. The quality of the plant fossil record also makes paleobotanical data highly informative about the historical pattern of plant evolution. It is this pattern, and its congruence with patterns in the characters of living and fossil plants — as summarized in a classification — that is the focus of this chapter.

Download Full-text